Air bearing magnetic transducer



March 28, 1967 N. J. APPLETON 3,311,902

AIR BE ARING MAGNETIC TRANSDUCER Original Filed Feb. 2, 1955 3Sheets-Sheet l Y 21. If? L E /5 1 5 /761 t 3' INVENTOR NORMAN J.APPLETON March 28, 1967 APPLETO-N 3,311,902

7 AIR BEARING MAGNETIC TRANSDUCER Original Filed Feb. 2, 1955 3Sheets-Sheet 2 INVENTOR NORMAN J. APPLETON March 28, 1967 N. J. APPLETON3,311,902

AIR BEARING MAGNETIC TRANSDUCER Original Filed Feb. 2, 1955 5Sheets-Sheet 3 266 .290. gym

INVENTOR NORMAN J. APPLETON United States Patent Ofiiice 3,3 I Ifid?Patented Mar. 28, 1967 7 Claims. (Cl. 340-174.1)

This application is a division of application Ser. No. 485,746 filedFeb. 2, 1955.

This invention relates to recording apparatus, and more particularly tomagnetic recording apparatus including head mounting means.

The memory or information storage unit is an essential component of thepresent day high speed electronic computers. The continued developmentof such computers has required the creation of recording or informationstorage units capable of delivering and receiving great quantities ofinformation at high speed. In addition information which has been storedmust be accessible when desired with a minimum delay period. From apractical point of view the storage device should have a high storagecapacity to space ratio, as well as be efiicient in operation,inexpensive to manufacture and maintain, and of high operatingreliability.

Accordingly a primary object of the invention is to provide a new andimproved magnetic head member mounting means.

The invention accomplishes the above object by providing a revolvingsignal storage body having a plurality of plane record surfaces and aslider block head member with its bearing and signaling surfaceproximate the record surface.

The revolving signal storage body may be comprised of a plurality ofdisks, each having a pair of plane record surfaces. The disks are spacedalong their axis of rotation so that their intersurfaces form aplurality of interstices. A pair of slider block members are positionedwith their signaling surfaces respectively proximate the recordinter-surfaces forming one of the interstices.

The member positioning means comprises a pair of member suspending unitsconnected at the end of a member locating arm which are adapted to bereceived within any one of the interstices. The member suspending unitsrespectively engage the slider block head members for adjusting theirinclination and elevation with respect to their proximate recordsurfaces, while the member loeating arm is transversely movable forcontrolling the trace path of the members over their respective recordsurfaces.

A carriage unit supports the member locating arm and is positionablealong the axis of the rotating record body when the arm is retracted.This allows the locating arm to be situated for transverse movement intoany selected one of the interstices.

Control means is provided for positioning the locating arm and thecarriage units.

The foregoing and other objects of the invention will become moreapparent as the following detailed description of the invention is readin conjunction with the drawings in which:

FIGURE 1 is an elevational view of a recording apparatus embodying theinvention,

FIGURE 2 is an enlarged elevational view of the carriage unit and themember positioning means in its retracted position as shown in FIGURE 1,

FIGURE 3 is a plan view taken on the line 3-4 of FIGURE 2,

FIGURE 4 is a fragmentary sectional view taken on the line 4-4 of FIGURE3 illustrating in detail the carriage unit position retaining mechanism,

FIGURE 5 is a sectional view of the carriage unit and a portion of themember locating arm taken on the line 5--5 of FIGURE 3,

FIGURE 6 is a side elevational view of the carriage unit and the memberpositioning means in its retracted position taken on the line 66 ofFIGURE 2,

FIGURE 7 is a view similar to that of FIGURE 2 showing the memberpositioning means extending into an interstice of the revolving recordbody,

FIGURE 8 is a sectional view taken on the line 8.8 of FIGURE 7 showingin exaggerated form for purposes of illustration the angular andpositional relationships between the slider block head members and theirproximate record surfaces when positioned by their suspending units andmember locating arm within an interstice,

FIGURE 9 is a view similar to FIGURE 8 taken on the line 99 of FIGURE 7,

FIGURE 10 is a plan view of a modified member positioning meansutilizing U-shaped resilient leaf elements,

FIGURE 11 is a side elevational view of the member positioning meansshown in FIGURE 10,

FIGURE 12 is another embodiment of the member positioning meansutilizing a pair of forked control elements,

FIGURE 13 is a side elevational view of the positioning means shown inFIGURE 12,

FIGURE 14 is still another modified member positioning means utilizingparallel pairs of resilient leaf elements for pivotally suspending theslider block head members, and

FIGURE 15 is a side elevational view of the modified positioning meansshown in FIGURE 14.

Refer now to FIGURE 1 in particular which discloses a recordingapparatus having a frame structure 18 comprising a base portion 20, avertical supporting portion 22 and a top portion 24 A revolving recordbody 26 is supported by the frame structure 18 and comprises a drivemotor 28 resting upon the base portion 20. The output shaft of the motor28 is connected to the lower end of a rotatable shaft element 30 by acoupling unit 32. The upper end of the shaft element 30 is receivedthrough a ball bearing unit 33 mounted on the top portion 24 of theframe structure 18. In this manner the shaft element 30 is positionedfor rotation about a vertical axis.

The rotatable shaft element 30 receives along its length a plurality ofparallel information storage or record disks 34- each provided with apair of plane record surfaces 36, 38 and a central opening 46] throughwhich the shaft element 31) is received (FIGURE 7). A plurality ofspacer units 42 are also received along the shaft element 30 betweenadjacent record disks 34. The spacer units 42 uniformly space theintersurfaces 36, 38 of adjacent record disks 34 forming a plurality ofrespective interstices 44 along the shaft element 30.

A compression ring 46 which is locked with the rotatable shaft element3t; at its lower end supports the record disks 34 and spacer units 42positioned above it about the shaft element 30. A securing nut 48threadedly received at the threaded upper end 50 of the shaft element 30applies a compressive force to the record disks 34 and spacer units 42clamping them for rotation with the shaft element 30. The spacer units42 and the disks 34 may also be keyed to the shaft element 30 to insureagainst slippage.

It is noted that by use of a plurality of recording disks 34- which maybe removed from the shaft element 30 and replaced by other disks 34, arecording body 26 of high versatility is achieved. The capacity of therecording body 26 may also be augmented or reduced by adding disks 34 orremoving them from the assembly.

In operation the motor 28 drives the rotatable shaft 30 at a constantspeed. The recording disks 34 rotate with the shaft 30 about itsvertical axis which is also its axis of generation. The recordingapparatus utilizes the revolving record body 26 for storing informationby magnetic recordation upon the parallel plane record surfaces 36, 38of the disks 34. The arrangement of the disks 34 of the revolving recordbody 26 provides a memory or information storage unit which is highlyeflicient in space utilization and provides a high degree ofaccessibility to stored information.

A pair of carriage guiding rod elements 52 are positioned parallel withthe shaft element 30 having their lower ends connected with the baseportion 20 and their upper ends joined to the top portion 24 of theframe structure 18. The rod elements 52 are provided with a plurality ofdetent notches or stops 54 (FIGURE 2) which are equally spaced alongtheir lengths corresponding to the spacings between the record disks 34of the record body 26.

Refer to FIGURES 2, 3 and 4 showing in detail a carriage unit 56 whichis provided with two openings 58. The openings 58 respectively receivethe rod elements 52 for guiding and positioning the carriage unit alongthe rotatable axis of the record body 26.

The carriage unit 56 may be retained in any one of a plurality ofpositions, corresponding to the stops 54 along the rod element 52 by apair of carriage locking devices 60. The locking devices 60 eachcomprises a spring loaded ball respectively adapted to engage the stops54 of the rod elements 52. This spring action is sufficient normally tosupport the carriage unit 56. However, when a sufficient force isapplied in the direction along the rod elements 52 the carriage unit 56will overcome the locking action of the devices 60 and permit relocationof the carriage unit 56.

The carriage unit 56 supports a member positioning means comprising anelongated member locating arm 62 and a pair of member suspending units64 and 64 which are attached at the extending end 66 of the arm 62. Thecarriage unit 56 is provided with a horizontal opening 68 therethroughslidably receiving the locating arm 62 for movement between retractedand extended positions. The locating arm 62 is supported for motion inits extending direction toward the axis of rotation of the record body26. The carriage unit 56 is also situated by the locating action of itslocking devices 60 and the detent stops 54 of the rod elements 52 sothat the locating arm 62 with its extending end 66 when in its extendedposition is received Within an interstice 44 formed by the intersurfaces36, 38 of adjacent record disks 34. It is noted that the motion of thearm 62 in the radial direction towards the axis of rotation of therecord body 26 moves transverse to the direction of motion of the planeintersurfaces 36, 38.

When the locating arm 62 is moved to its fully retracted position itsextending end 66 is completely withdrawn from the interstice 44. When inits retracted position the arm 62 will not interfere with the relocationof the carriage unit 56 along the rod element 52. In this manner thecarriage unit may be positioned or situated so that the arm 62 can beextended into any selected one of the interstices 44 of the record body26.

The pair of member suspending units 64, 64' are laterally attached atthe extending end 66 of the locating arm 62 for respectively positioninga pair of slider block head members 70, 79.

The member suspending unit 64 is provided with a first rectangular frameelement 72 having a pair of pivots 74. The pivots 74 engage the sliderblock head member 70 along an axis of rotation between and parallel withthe leading edge 76 and the trailing edge 78 of thehead member 70 (seeFIGURES 3 and 8). More particularly the axis of rotation provided by thepair of pivots 74 is located from the trailing edge 78 a distance ofapproximately one-third the distance between the leading and trailingedges 76, 78. While this axis of rotation provides angular adjustment inthe longitudinal direction between the edges 76, 78 of the slider blockhead member 70, a pivot control spring element 80 is connected betweenthe frame element 72 and the leading edge 76 of the head member 70tending to maintain the head member 70 in substantial alignment Withinthe frame element 72. The purpose of the control spring element 80 (seeFIGURE 3) is to prevent substantial misalignment of the block headmember 70 while still allowing sufficient pivot action for longitudinaladjustment of the member 70. A similar result may be obtained bytightening the pivots 74 thereby increasing the frictional resistance tomotion of the member 70 about its axis of longitudinal rotation.

A second J-shaped frame element 82 is provided with a pair of pivots 84engaging the rectangular frame element 72 along a central axisperpendicular to the pivot axis of the head member 70. Rotation of therectangular frame element 72 about its axis provides adjustment of thelateral inclination of the head member 70. The pivots 84 may betightened to produce sufficient resistance to rotation preventingmisalignment of the element 72 while yet allowing sufficient movementfor adjustment purposes.

The long leg 86 of the frame element 82 extends in the direction of thelocating arm 62 and is connected therewith by a pair of pivots 88. Theaxis of rotation of the frame element 82 is parallel to the axis ofrotation of the head member 70 as Well as to the direction of slidingmotion of the locating arm 62. When the slider block head member 70 iswithin an interstice 44 of the record body 26, rotation of the frameelement 82 about its axis adjusts the elevation of the bearing andsignaling surface 90 of the member 70 with its proximate top recordsurface 36 of the lower disk 34, while rotation of the member 70 aboutits pivot axis adjusts the longitudinal inclination of its surface 90with the record surface 36.

A member loading means comprising a spring 92 exerts a force on theJ-shaped frame element 82 which urges the bearing surface 90 of the headmember 70 in a direction towards its proximate record surface 36.

The member suspending unit 64' which is laterally positioned with andsimilar to the unit 64 acts to adjust the elevation and the longitudinaland lateral inclination of the bearing and signaling surface 90' of theslider block head member 70' with respect to its proximate bottom recordsurface 38 of the upper disk 34 when 'within an interstice 44. The headmember 70' is likewise urged by a member loading spring 92' towards itsproximate record surface 38.

The slider block head members 70, 70' each have provided within them aplurality of loop elements 91, 91. Each loop element 91, 91' provides amagnetic path having a gap 93, 93' proximate the signaling surfaces 90,90 and 'a respective energizing winding 95, 95' about it. The loopelements 91, 91' may be positioned with their gaps laterally arrangedacross the bearing and signaling surfaces 90, 90', of the members 70,70', for purposes of recording and receiving information concurrently ina plurality of channels. Although the longitudinal position of thetransducer elements 91 and 91' within the transducer blocks 76 and 70'may be largely a matter of choice, it will be apparent that for gooddesign practice the gaps 93 and 93 should be located at a stable pointnearest the recording surfaces of the disks. A typical location would,of course, be where the gaps 93 and 93' are at or adjacent the trailingedges of the active surfaces 90 and 90' of the blocks 70 and 70. Thispoint of location of the gaps in the active surfaces 90 and 90' followsfrom the fact that the blocks 70 and 70' float at an inclined angle tothe recording surfaces of the disks, and thus the trailing edges of theblocks 70 and 70' are nearest the surfaces of the recording disks. Thewindings 95, 95' are connected to pairs of wires which form a flexiblecable 94, 94- which passes from its slider block head members 70, 70'into the locating arm 62. The cables extend through the locating arm 62to its other end Where it is joined to a cable loop 96 connecting withthe stationary frame structure 18 for communicating information signals.The loop 96 allows movement of the locating arm 62 and the carriage unit56 without interference.

In a signal receiving or recording operation the locating arm 62 isextended into an interstice 44 of the record body 26 while the body 26is rotating at a constant speed. The spring loaded member suspendingunits 64, 64' respectively urge the bearing and signaling surfaces 90,90 of their respective slider block head members 70, 70' in thedirection toward their proximate record surfaces 36, 38. Reference onlywill be made now to the operation of the slider block head member 70,since the member 70' operates in a similar manner with respect to itsproximate record surface 38.

Because of the relative sliding motion between the bearing and signalingsurface 90 of the head member 70 and its proximate record surface 36,the fluid (atmospheric air in this case) within the interstice 44passing between these surfaces develops a force which acts through thecenter of the pivot axis of rotation of the head member '70. This forcewhich is inversely related to the clearance distance between the bearingand record surfaces 36 tends to increase the clearance distance, therebycounteracting the force exerted by the member loading spring Q2.

A detailed analysis of slider bearing theory is given in an article byM. Muskat, F. Morgan and M. W. Meres in an article entitled TheLubrication of Plane Sliders of Finite Width published in the Journal ofApplied Physics of Man, 1940, pages 208 and 219 inclusive. This articlealso indicates that the fluid force developed is a function of thelongitudinal angle of inclination of the slider block and is related tomany other factors. The angle of inclination is also shown to be afunction related to the position of the pivot axis between the leadingand trailing edges of the slider block.

From the overall practical aspect, the slider block head member '70 wasfound to operate most satisfactorily for the purposes of a relativelyconstant predetermined clearance distance, by positioning the pivot axisparallel to and intermediate the leading and trailing edges, a distancefrom the trailing edge 78 of approximately one-third the distancebetween the edges 76, 78. This location was not found to maximize theforce developed by the fluid, but did maintain optimum operatingstability and constant clearance distance under practical operatingcircumstances.

With the pivot axis of the slider member 70 fixed the block withautomatically assume a predetermined longitudinal angle of inclinationand clearance distance with the moving record surface 36.

With the other relative factors fixed, a clearance distance between thebearing and signaling surface 90 and the record surface 36 may bedetermined by adjusting the loading force exerted by the spring 92.. Theclearance distance between the surfaces M 36 which is maintained is theposition of equilibrium wherein the fluid force and the loading forceare balanced. Because of this, the clearance distance may be set byvarying the force exerted by the loading spring 92. Thus, by increasingthe force of the spring 92, a new equilibrium position of reducedclearance will be maintained, whereas decreasing the force of spring 92will increase the clearance distance at which the fluid force is counterbalanced. It is also noted, that variation in the fluid viscosity andthe relative speed of the surfaces 90, 36 will also influence theequilibrium clearance distance.

Although in this case the slider action takes place in a fluid ofatmospheric air, fluids having other viscosities 6 may be used, theforce developed by the fiuid upon the slider block member 70 beingdirectly proportional to its viscosity.

The clearance distance is maintained substantially constant by theresulting unbalanced forces which act upon the slider block head member75 when it is not in its equilibrium position. These forces tend toaccelerate the member 70 towards its equilibrium position. By reducingto a minimum the mass associated with the slider block head member 70,an unbalanced force acting on the member produces an acceleration manytimes that of gravity which is constantly effective to maintain thepredetermined clearance distance between the bearing and signalingsurface and the record surface 36.

The many advantages of this means for maintaining a constant clearancedistance for tracking in a magnetic recording apparatus operating athigh speed will at once be obvious. One of the great advantages is thereliability and the inexpensive construction of the signaling apparatusprovided.

The importance of maintaining a constant clearance distance between therecording surface 90 of the head member 70 and the record surface 36 ofthe disk 34- for the purpose of magnetic recording when high reliabilityis essential, is also well known. Thus by maintaining a substantiallyconstant clearance this apparatus allows the head member 70 to recordmagnetic signals in a plurality of channels in a path traced over thesurface of the disk 34. In this apparatus a substantially constantclearance is maintained even though the contour of the disk is notperfectly plane due to irregularities in manufacture and assembly,variations in temperature and deformation with time. Greater toleranceis thus allowed by the use of a slider block head member 70 whichreduces the cost of manufacturing and it makes the operation of thedisclosed signaling apparatus practicable.

Merely for illustration and not for purposes of limitation the recorddisk 34 may be made of aluminum material which has been plated with amaterial having good magnetic recording properties such as cobalt nickelalloy. Disks having a diameter of approximately 20 inches and revolvingat a speed of 1200 revolutions per minute, with the outer area beingused for recording purposes were found satisfactory. The disks used alsohad a thickness of five-hundredths of an inch, the distance between theinter-surfaces of the interstices 44 being three-sixteenths of an inch.

Still merely for purposes of illustration, the slider block head member70 having a longitudinal distance of three-eighths of an inch betweenits leading and trailing edges 76, 78 while being one-half of an inchwide with its axis of rotation one-eighth of an inch from the trailingedge was found to operate very satisfactorily in an air atmosphere. Withthe mass associated with the slider block head member '70 being aboutthree grams and a force of six ounces being exerted by the memberloading spring 92, a clearance distance which was determined to besubstantially four ten-thousandths of an inch was maintained between thebearing and signaling surface 9 0 and the record surface 36. Asufliciently high acceleration was developed by the unbalanced forcestending to maintain the member at its predetermined clearance distancewith good stability. The use of this structure allowed recordation anddelivery of information signals with high reliability and accuracy.

The efficiency of the recording apparatus is enhanced by the use of thetwo slider block head members 70, 70' in side by side relationship,whereby the members may concurrently act on their proximate recordsurfaces 36, 38 within an interstice 44. This allows them tosimultaneously perform recording operations whereby information isdelivered to or received from the record body 26.

The leading and trailing edges '76, 73 of the members 70, 70' arepositioned transverse the direction of motion of their proximate recordsurfaces 36, 38. Thus by extending the locating arm 62 to respectivepredetermined positions, information may be recorded in concentric pathstraced over the intersurfaces 36, 38. This information is then readilyaccessible by goin to the predetermined location for the desiredinformation. Information may also be recorded in a spiral path on eachof the intersurfaces by progressively extending the locating arm 62 inthe transverse direction during the recording process.

By these means the recording apparatus may store information inconcentric loops or in a spiral path as may be determined underparticular conditions of operation.

Since the fluid force counteracting the loading force of the springs 92,92 is no longer present when the locating arm 62 is in its fullyretracted position, a pair of earns 98, 98 extending from the carriageunit 56 are provided for respectively engaging the J-shaped frameelements 82, 82 of the member suspending units 64, 64.

In the absence of the cams 98, 98' the force of the loading springs 92,92 upon the suspending units 64 would result in misalignment of the headmembers '70, 70. In addition to possible damage to the suspending units64, 64 and the head members 70, 70, serious dinioulty also would beencountered under such circumstances when the locating arm is extendedfor entrance into a selected interstice 44.

The cams 98, 98' provide the necessary guiding action during thetransitional period between static and dynamic action of the sliderblock head members '70, 70'. The tapered or sloped end 100 of the cam 98acts to gradually lower the bearing surface 90 of the member 70 towardsthe record surface 36 approaching the predetermined clearance distanceas the full fluid force is developed supporting the member 70 againstthe loading force. The tapered portion 100 of the cam 98 serves asimilar purpose with respect to its slider block head member 70'.

The carriage unit 56 is also provided with an arm locking solenoid 102(see FIGURE having a movable key 104 which is normally urged in thedirection for engaging the opening 106 in the locating arm 62. 'Inoperation when the locating arm 62 is in its fully retracted position,its opening 106 is in alignment with the key 104 of solenoid 102. Thekey 104 being normally urged in the direction towards the arm 62, may atthis time enter the opening 106, locking the arm 62 in its retractedposition. The arm 62 can be released for transverse sliding actionwithin the carriage unit 56, by energizing the solenoid 102 causing itto withdraw the key 104 as shown in FIG- URE 5. The solenoid 102 isconnected to a source of energy by the cable loop 96 which returns tothe frame structure 18.

In addition to the safety feature provided by locking the arm 62 in itsretracted position preparatory to moving the carriage unit 56 along therod element 52, in view of the following description it will becomeevident that relocation of the carriage unit 56 can only take placeafter the arm 62 has been locked in its retracted position.

The movement and positioning of both the locating arm 62 and thecarriage unit 56 are provided by a flexible control cable 110 (FIGURE1). The control cable 110 forms a loop which passes about the four guidewheels 112 which are connected with the frame structure 18, makesseveral loops about a cable driving drum 114, and has its ends 116, 118connected respectively at opposite ends of the locating arm 62. Thecable end 116 passes downwardly along the guide rod 52, passes aroundthe top guide wheel 120 which is connected with the carriage unit 56,and moves horizontally along the locating arm 62 being attached at theremote end 122 of the arm 62. The arm 62 is also provided with alongitudinal groove 124 which receives within it the cable end 116,clearly shown in FIGURES 3 and 5.

In a similar manner the control cable end 118 passes upwardly along theguide rods 52 to the carriage unit 56, where it passes about a lowerguide wheel 126 which is also connected with the carriage unit 56. Thecable 8 end 118 then is received within a groove 128 in the bottomsurface of the arm 62 and passes in the direction towards the extendedend of the arm 62 to a point of attachment 130 (see FIGURE 5).

In operation, the drum 114 is driven in either the clockwise or counterclockwise direction by means of a gear reduction unit 132 which isenergized by a reversible drive motor 134. If the drum 114 is driven inthe clockwise direction, the control cable will also move in thisdirection. This will cause the end 116 of the cable 110 to exert a forceon the arm 62 causing it to move towards its extended position when itis not locked in its retracted position. The end 118 at the same timewill pass about the lower pulley wheel 126 allowing and controlling theextending motion of the locating arm 62.

In a similar manner the counter clockwise rotation of the drum 114imparts a like motion to the control cable 110. The control cable 110now acts upon the locating arm 62 moving it towards its retractedposition.

By such operations the position and movement of the locating arm 62 isaccurately controlled by the control cable 110 which responds to controlenergization of the reversible motor 134. This provides an accuratemeans for controlling the trace path of the slider block members 70, 70with respect to the plane record surfaces 36, 38 within an interstice 44of the revolving record body 26. The head members 70, 70 may bepositioned for recording information at any desired location, and may bereturned to any such location to receive the information previouslystored.

After information has been stored or received at the intersurfaces of aselected interstice 44, the locating arm 62 may be retracted to itslocked position preparatory to relocating the carriage unit 56, byactuating the control cable 110 in the counter clockwise direction.

With the arm 62 locked in its retracted position by the action of thesolenoid 102, further motion of the control cable 110 will cause thecarriage unit 56 to move along the guide rods 52. The carriage unit 56will not be moved along the guide rods 52 unless the locating arm 62 isin its retracted locked position because of the retaining action of thecarriage locking devices 60. When the positioning arm 62 is locked,however, the retaining action of the locking device 60 can be overcomeby force which is now exerted on the carriage unit 56 by the controlcable 110.

By rotating the drum 114 in its clockwise direction the carriage unit 56will move upwardly along the guide rods 52, and will move downwardlywhen the motor 134 reverses the movement of the control cable 110. Inthis manner the carriage unit 56 may be situated in a correspondingretaining position for extending the arm 62 into any selected one of theinterstices 44 of the revolving record body 26. When so positionedenergization of the solenoid 102 will unlock the locating arm 62allowing it to move towards its extended position into the selectedinterstice 44 upon the clockwise motion of the control cable 110.Subsequent movement of the control cable 110 will serve to accuratelyposition and move the arm 62, while the carriage unit 56 is maintainedin its set position by the locking devices 60. The locating arm 62 maythen again be locked in its retracted position when a new carriagelocation is to be assumed.

The advantages and safety features of the control system and itsinherent efiiciency because of its alternate control of the positioningarm 62 and the carriage unit 56 are noted. It also provides a controlmeans whereby information stored in predetermined locations is madereadily available in a high speed recording apparatus with a minimum ofaccess time expended.

Refer now to FIGURES 10 and 11 which show a locating arm 162 with amodified extending end 166 and member suspending units 164, 164.

The member suspending unit 164 is comprised of a flexible and resilientsubstantially U-shaped leaf element 168 having its leg ends 169connected to and radially extending from the end 166 of the arm 162. Thecentral portion 172 of the leaf element 168 supports a block head member170, which is provided with a lateral groove 174 in its distal surfaces176. The groove 174 which is parallel to the leading and trailing edgesof the member 170 is located intermediate these edges.

The end of a loading spring 178 contacts the member 170 at the center ofits groove 174 urging the bearing and signaling surface 180 (FIGURE 11)towards its proximate record surface when within an interstice 44 of therotating record body 26. The flexibility of the resilient leaf element168 allows the member 17%} to adjust its elevation and angularinclination both laterally and longitudinally with respect to itsproximate record surface.

The end portion of the loading spring 178 passes through an opening in apivoted rod 182. The rod 182 may be engaged by a cam of its carriageunit when the arm 162 is retracted. In this manner the force exerted bythe end of the spring 178 is removed from the head member 170 when it iswithdrawn from an interstice of the rotating record body 26. The leafelement 163 then operates to maintain the alignment of the member 170for insertion within a selected interstice, after which the rod 182 isdisengaged and the force of the loading spring 178 is again applied tothe head member 170.

The member suspending unit 164' and its slider block head member 170 aresimilar in construction and operation to those just described. Themember 170 however, has its signaling surface 180' adapted forpositioning proximate a record surface 38 of the disks 34.

The slider block head members 170, 170 are also respectively providedwith signal cables 1%, 1% which are received through the locating arm162.

Refer now to FTGURES l2 and 13 which show another type of membersuspending unit 264 which is similar to suspending unit 164 except forthe means of applying the loading force to the slider block head member.

The unit 264 comprises a U-shaped resilient and flexible leaf element268 which supports its slider block head member 270 at its centralportion 272. The member loading force is applied to the member 270 by aY-shaped or forked control element 274 having leg portions 276 and astem portion 278. The ends of the leg portion 276 pivotally engage theleading and trailing edges of the member 270 about a centrallongitudinal axis providing adjustment of lateral inclination. The stemportion 278 of the forked element 274 is positioned along an axis whichlies intermediate and parallel with the leading and trailing edges ofthe slider block lhead member 270. This axis which is positionedintermediate the leading and trailing edges of the member 270, allowsrotation for adjusting the longitudinal inclination of the member 270.The stem portion 278 is received within a groove 279 in a stud 280 aboutwhich it pivots under the force of the member loading spring 282 foradjusting the elevation of the signaling surface 284 (FIGURE 13) of themember 270.

The extending end of the stem portion 278 of the forked element 274 maybe engaged by a cam when the locating arm 262 is retracted for thepurpose of counterbalancing the force of the loading spring 282.

The member suspending unit 264' and its slider block head member 270 aresimilar to those just described. The members 270, 270" are laterallypositioned and respectively adapted for recording on and receivinginformation from their proximate record surface. The cables 290, 290"are provided for communicating with their respective head members 270,270'.

Refer to FIGURES l4 and 15 which illustrate another modified form of amember suspending unit 364 which is supported at the extending end 366of a locating arm 362. A second suspending unit 364 is laterallypositioned with the unit 364 and similar thereto.

The member suspending unit 364 comprises a parallel pair of resilientand flexible leaf elements 368 which have their ends connected to andradially extending from a rotatable shaft 370*. The leaf elements 363are provided with a pair of pivots 372 which engage a slider block headmember 374 along an axis intermediate and parallel to its leading andtrailing edges. The deflection of the resilient leaf element 368provides for the adjustment of a lateral inclination of the head member374, while its pivotal action allows for the adjustment of thelongitudinal inclination of the head member 374.

A pivot control spring 3-76 which is positioned between the end of oneof the leaf elements 368 and the leading edge of the head member 374maintains the longitudinal inclination of the slider block head member374 within a desired range. In this manner the slider block head member376 is maintained in a substantially aligned position even when themember is withdrawn from an interstice 44 of the rotating record body26.

A clockwise torque force is exerted upon the rotatable shaft 370 by theend of a member loading spring 378 acting on a lever 380 which extendsfrom the shaft 370. This torque force is transmitted by the parallellead elements 368 and 368 respectively of the suspending units 364, 364urging the bearing surfaces of their associated head members 374 and 374towards their respective record surfaces when within an interstice 44 ofthe body 26.

When the locating arrn 362 is withdrawn from an interstice 44 of thebody 26, a cam may be provided adapted to engage the lever 380' forcounter-balancing the force of the member loading spring 378. It isnoted that a great advantage of the torque loading means provided by thelocating arm 362 and the suspending units 364, 3-34 is that it resultsin a greatly simplified structure. Such a structure also tends tominimize the mass associated with the slider block head members 374,374.

It Will be obvious to those skilled in the art that the invention mayfind wide application with appropriate modification to meet the variousdesign circumstances but without substantial departure from the essenceof the invention.

What is claimed is:

1. In a magnetic recording apparatus, a slider block head membercarrying a magnetic transducer and having a leading edge and a trailingedge, said member being adapted for use with a body having a movingrecord surface that tends to move a layer of ambient fluid, and headmember positioning means including pivot bearing means coupling saidhead member positioning means to said head member to allow pivoting ofsaid head member about an axis intermediate and parallel with itsleading and trailing edges for adjusting the inclination of said memberwith the record surface of said body simultaneously to allow the forceof said fluid to displace said member from said surface, said axis beingpositioned from the trailing edge approximately one-third of thedistance between the leading and trailing edges of said member, saidhead member positioning means including a frame element surrounding saidhead member and carrying said pivot bearing means, said head positioningmeans further including a control spring element attached to said frameelement and adapted to engage the leading edge of said head member tohold same in substantial alignment with said frame element.

2. A recording apparatus comprising a body provided with a recordsurface; a slider block head member having a leading edge, a trailingedge and a bearing and signaling surface proximate a portion of therecord surface of said body; said head member and said body beingrelatively movable whereby the relative motion causes a fluid force tobe exerted on the bearing surface of said head member in manner tomaintain said head member displaced from said body; and suspension meansyieldably supporting said head member in proximate relation With therecord surface of said body; said suspension means comprising first,second and third frame elements nested together to form a gimbalmounting structure for the head member, said first fra me elementpivotally engaging said member on an axis parallel with its leading andtrailing edges for adjusting the inclination of said member with therecord surface of said body, said axis being positioned closer to thetrailing edge of said member, said second frame element pivotallyengaging the first frame element along an axis perpendicular to thepivotal axis of said member for adjusting the lateral inclination ofsaid member, said third frame element pivotally engaging said secondframe element along an axis perpendicular to the lateral pivot axis ofsaid first frame element for adjusting the elevation of said member withthe record surface of said body, a pivot control spring elementconnected between said member and said first frame element and a memberloading means exerting a force through the center of the member pivotaxis urging said member in a direction towards said record surface tothereby counteract the fluid force exerted on said head member andmaintain a certain spacing between said head member and said recordsurface.

3. In a recording apparatus; a slider block head member with a leadingedge and a trailing edge adapted for use with a body having a movingrecord surface carrying with it a layer of fluid; member positioningmeans comprising first, second and third frame elements, first pivotbearing means coupling said first frame element to said member on apivot axis parallel with its leading and trailing edges for adjustingthe inclination of said member with the record surface of said body inresponse to the force of said fluid on said member; said aXis beingpositioned closer to the trailing edge than to the leading edge of saidmember; second pivot bearing means coupling said second frame element tothe first frame element along an axis perpendicular to the pivotal axisof said member for adjusting the lateral inclination of said member; athird pivot bearing means coupling said third 12. frame element to saidsecond frame element along an axis perpendicular to the lateral pivotaxis of said first frame element for adjusting the elevation of saidmember with the record surface of said body.

4. The apparatus of claim 3 wherein there is further included, a memberloading spring carried by said third frame element exerting a forcethrough the center of the member pivot axis urging said member in thedirection towards said record surface thereby opposing the force of saidfluid.

5. In combination, a slider block head member having leading andtrailing edges, a support structure for said head member adapted topermit said head to fioat over a moving recording surface, said supportstructure comprising (1) a first yoke member at least partiallysurrounding the perimeter of said head [member and pivotally engagingsaid head member along an axis parallel to the leading and trailingedges thereof, and (2) a second yoke member at least partiallysurrounding said first yoke member and pivotally engaging said firstyoke member along an axis at right angles to said first-mentioned axis.

6. The structure of claim 5 wherein there is further included in thesupport structure an arm which pivotally engages said second yoke memberalong an axis parallel to the first-mentioned axis.

7. The structure of claim 5 wherein the pivotal engagements recitedtherein are through pivot bearings.

References Cited by the Examiner UNITED STATES PATENTS 2,862,781 12/1958Baumeister 340--174.l

BERNARD KONICK, Primary Examiner.

5 IRVING L. SRAGOW, A. I. NEUSTADT, N. N.

3. IN A RECORDING APPARATUS; A SLIDER BLOCK HEAD MEMBER WITH A LEADINGEDGE AND A TRAILING EDGE ADAPTED FOR USE WITH A BODY HAVING A MOVINGRECORD SURFACE CARRYING WITH IT A LAYER OF FLUID; MEMBER POSITIONINGMEANS COMPRISING FIRST, SECOND AND THIRD FRAME ELEMENTS, FIRST PIVOTBEARING MEANS COUPLING SAID FIRST FRAME ELEMENT TO SAID MEMBER ON APIVOT AXIS PARALLEL WITH ITS LEADING AND TRAILING EDGES FOR ADJUSTINGTHE INCLINATION OF SAID MEMBER WITH THE RECORD SURFACE OF SAID BODY INRESPONSE TO THE FORCE OF SAID FLUID ON SAID MEMBER; SAID AXIS BEINGPOSITIONED CLOSER TO THE TRAILING EDGE THAN TO THE LEADING EDGE OF SAIDMEMBER; SECOND PIVOT BEARING MEANS COU-